Why is black oil coming out of exhaust?

[stingyraisin]

I have a 1997 130 hp Johnson. I recently got it running after sitting up about a year and 1/2. This engine self mixes oil and gas. My question is why does burnt oil backfire out of the exhaust once it gets running? My thought is that the diaphram that adjust the oil fuel mixture needs adjusting. It may be something else altogether. Any advice would be appreciated.

 

[ezeke]

Re: Why is black oil coming out of exhaust?

The black oil is unused excess oil which is normal, especially if the engine was fogged before storage. If it continues in large amounts, you may have a piston ring or two that has stuck in a piston.

You may want to de-carbon the engine if it has not been done.

 

[kenmyfam]

Re: Why is black oil coming out of exhaust?

As said, most likely unburnt 2 stroke oil. Does it smell of gas ???

 

[ezeke]

Re: Why is black oil coming out of exhaust?

Another possibility is that you could have an air/fuel leak on the gasoline supply side of the pump which will cause the pump to over-oil: http://www.youtube.com/watch?v=SEbW-6eOc5I